Luke Bryan is not only a judge on American Idol, but now the official guitar tuner as well!

Many contestants who are auditioning this season also want to show off their instrumental chops. In several cases, their guitars were out of tune, to the judges' dismay. Katy Perry calls on Bryan to tune each of the contestant's guitars when needed.

"Katy has made me the on-site guitar tuner, which is a little scary.," Bryan says in the video above. The video then cuts to a slew of instances of Perry screaming, "Luke!" It even shows a time when Bryan broke a guitar string, something that Perry claims is her greatest fear and pet peeve.

Even though Perry made Bryan the official tuner, she likes to weigh in on how to tune it and what to do, to which Bryan yells at her, "I know, Katy!"

"When you see me struggling, tuning the guitar, it's never my fault — it's always the guitar's fault," he observes.

Perry eventually grabs a guitar from Bryan's hand, clearly frustrated. After tuning it perfectly, Perry sings to Bryan, "Anything you can do I can do better," to which Bryan sings "I can do anything better than you." Perry screams, "No you can't," and Bryan fittingly replies, "Yes I can." An exasperated Lionel Richie finally weighs in, comically addressing the bickering pair, "Children! Children!"

The judges' camaraderie this season has been one of the most important elements of the show. American Idol airs on ABC Sundays and Mondays at 8PM ET.

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